.page-about {
  background: var(--rk-navy);
  color: var(--rk-paper);
  font-family: var(--rk-sans);
  overflow-x: clip;
}

.page-about a {
  color: inherit;
}

/* ---------- 右侧固定锚点索引 ---------- */
.page-about .pa-rail {
  display: none;
}

@media (min-width: 1200px) {
  .page-about .pa-rail {
    display: block;
    position: fixed;
    top: 172px;
    right: 26px;
    width: 176px;
    z-index: 4;
  }
}

.page-about .pa-index {
  border-left: 1px solid var(--rk-grid);
  padding-left: 16px;
}

.page-about .pa-index .rk-index__title {
  font-family: var(--rk-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--rk-mist);
  margin: 0 0 14px;
  text-transform: uppercase;
}

.page-about .pa-index .rk-index__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .pa-index .rk-index__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--rk-mist);
  text-decoration: none;
  border-left: 2px solid transparent;
  padding-left: 8px;
  transition: color .18s var(--rk-ease), border-color .18s var(--rk-ease);
}

.page-about .pa-index .rk-index__link:hover,
.page-about .pa-index .rk-index__link:focus-visible {
  color: var(--rk-mint-soft);
  border-left-color: var(--rk-mint);
}

.page-about .pa-index .rk-index__link.is-active {
  color: var(--rk-paper);
  border-left-color: var(--rk-mint);
}

.page-about .pa-index .rk-index__num {
  font-size: 11px;
  color: var(--rk-amber);
  letter-spacing: .06em;
}

/* ---------- 首屏 ---------- */
.page-about .pa-hero {
  position: relative;
  padding: clamp(44px, 8vw, 100px) 0 clamp(48px, 7vw, 88px);
  overflow: hidden;
  border-bottom: 1px solid var(--rk-grid);
}

.page-about .pa-hero__block {
  position: absolute;
  top: -22%;
  right: -14%;
  width: 74%;
  height: 132%;
  background: var(--rk-navy-2);
  transform: rotate(-7deg);
  z-index: 0;
}

.page-about .pa-hero__grid {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    90deg,
    transparent 0 79px,
    rgba(38, 60, 92, .5) 79px 80px
  );
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, .85), transparent 78%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, .85), transparent 78%);
}

.page-about .pa-hero__inner {
  position: relative;
  z-index: 2;
}

.page-about .pa-hero__crumb {
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--rk-mist);
  display: flex;
  gap: 8px;
  margin-bottom: clamp(24px, 5vw, 48px);
}

.page-about .pa-hero__crumb a {
  color: var(--rk-mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.page-about .pa-hero__crumb a:hover,
.page-about .pa-hero__crumb a:focus-visible {
  color: var(--rk-mint-soft);
  border-bottom-color: var(--rk-mint);
}

.page-about .pa-hero__kicker {
  font-family: var(--rk-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--rk-amber);
  margin: 0 0 20px;
}

.page-about .pa-hero__title {
  margin: 0 0 clamp(20px, 3vw, 32px);
  max-width: 17ch;
  font-weight: 500;
  line-height: 1.06;
  letter-spacing: -.02em;
}

.page-about .pa-hero__title-line {
  display: block;
  color: var(--rk-mint-soft);
}

.page-about .pa-hero__lead {
  max-width: 34em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.78;
  color: var(--rk-mist);
  margin: 0 0 clamp(32px, 5vw, 52px);
}

.page-about .pa-hero__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--rk-grid);
  border: 1px solid var(--rk-grid);
}

@media (min-width: 680px) {
  .page-about .pa-hero__facts {
    grid-template-columns: repeat(3, 1fr);
    max-width: 860px;
  }
}

.page-about .pa-fact {
  background: var(--rk-navy);
  padding: 18px 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .pa-fact__num {
  font-size: clamp(26px, 3.4vw, 38px);
  font-weight: 500;
  line-height: 1;
  color: var(--rk-mint);
  letter-spacing: .02em;
}

.page-about .pa-fact__label {
  font-size: 13px;
  color: var(--rk-mist);
  line-height: 1.5;
}

/* ---------- 通用区块 ---------- */
.page-about .pa-section {
  padding: clamp(56px, 9vw, 112px) 0;
  border-bottom: 1px solid var(--rk-grid);
}

.page-about .pa-section__head {
  max-width: 46em;
  margin-bottom: clamp(32px, 5vw, 56px);
}

.page-about .pa-section__head .rk-kicker {
  font-family: var(--rk-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--rk-mint);
  margin: 0 0 14px;
}

.page-about .pa-section__head .rk-subtitle {
  margin: 0 0 18px;
  font-weight: 500;
  font-size: clamp(24px, 3.2vw, 34px);
  line-height: 1.24;
  letter-spacing: -.01em;
}

.page-about .pa-section__lead {
  color: var(--rk-mist);
  margin: 0;
}

.page-about .rk-prose {
  font-size: clamp(15px, 1.4vw, 17px);
  line-height: 1.78;
  color: var(--rk-mist);
  max-width: 34em;
  margin: 0 0 20px;
}

.page-about .rk-prose a {
  color: var(--rk-mint-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(23, 210, 166, .45);
}

.page-about .rk-prose a:hover,
.page-about .rk-prose a:focus-visible {
  border-bottom-color: var(--rk-mint);
}

/* ---------- 图片 ---------- */
.page-about .pa-figure {
  margin: 0;
  background: var(--rk-navy-2);
  position: relative;
  overflow: hidden;
  border: 1px solid var(--rk-grid);
}

.page-about .pa-figure__img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  max-width: 100%;
}

.page-about .pa-figure__caption {
  display: block;
  padding: 12px 16px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--rk-mist);
  border-top: 1px solid var(--rk-grid);
  background: var(--rk-indigo);
  letter-spacing: .02em;
}

/* ---------- 起点与初衷 ---------- */
.page-about .pa-origin {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 4vw, 56px);
  align-items: start;
}

@media (min-width: 900px) {
  .page-about .pa-origin {
    grid-template-columns: 6fr 5fr;
  }
}

.page-about .pa-origin__title {
  font-weight: 500;
  font-size: clamp(24px, 3.2vw, 34px);
  line-height: 1.24;
  margin: 0 0 20px;
  letter-spacing: -.01em;
}

.page-about .pa-origin__figure {
  clip-path: polygon(0 0, 100% 4%, 100% 100%, 0 96%);
}

/* ---------- 时间轴 ---------- */
.page-about .pa-section--flow {
  background: var(--rk-navy);
}

.page-about .pa-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 56px;
  position: relative;
}

.page-about .pa-timeline::before {
  content: "";
  position: absolute;
  left: 17px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background: var(--rk-grid);
}

.page-about .pa-timeline--continued {
  margin-top: clamp(24px, 4vw, 44px);
}

.page-about .pa-node {
  position: relative;
  padding-bottom: 22px;
}

.page-about .pa-node::before {
  content: "";
  position: absolute;
  left: -44px;
  top: 9px;
  width: 11px;
  height: 11px;
  background: var(--rk-amber);
}

.page-about .pa-fold {
  border: 0;
}

.page-about .pa-node__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  list-style: none;
  cursor: pointer;
  padding: 2px 0;
  position: relative;
}

.page-about .pa-node__head::-webkit-details-marker {
  display: none;
}

.page-about .pa-node__year {
  font-size: 15px;
  font-weight: 500;
  letter-spacing: .06em;
  color: var(--rk-amber);
  flex: none;
}

.page-about .pa-node__line {
  font-size: clamp(16px, 1.7vw, 19px);
  font-weight: 600;
  color: var(--rk-paper);
  line-height: 1.5;
  letter-spacing: -.01em;
}

.page-about .pa-fold__sign {
  position: relative;
  width: 12px;
  height: 12px;
  flex: none;
  margin-left: auto;
  align-self: center;
}

.page-about .pa-fold__sign::before,
.page-about .pa-fold__sign::after {
  content: "";
  position: absolute;
  background: var(--rk-mint);
  transition: transform .18s var(--rk-ease);
}

.page-about .pa-fold__sign::before {
  top: 5px;
  left: 0;
  width: 12px;
  height: 1px;
}

.page-about .pa-fold__sign::after {
  left: 5px;
  top: 0;
  width: 1px;
  height: 12px;
}

.page-about .pa-fold[open] .pa-fold__sign::after {
  transform: scaleY(0);
}

.page-about .pa-node__body {
  padding: 12px 0 0;
  max-width: 34em;
}

.page-about .pa-node__body p {
  margin: 0;
  font-size: clamp(15px, 1.4vw, 16px);
  line-height: 1.78;
  color: var(--rk-mist);
}

.page-about .pa-node__body a {
  color: var(--rk-mint-soft);
  text-decoration: none;
  border-bottom: 1px solid rgba(23, 210, 166, .45);
}

.page-about .pa-node__body a:hover,
.page-about .pa-node__body a:focus-visible {
  border-bottom-color: var(--rk-mint);
}

.page-about .pa-spine {
  max-width: 520px;
  margin: clamp(28px, 5vw, 48px) 0;
  clip-path: polygon(0 0, 96% 0, 100% 100%, 4% 100%);
}

@media (min-width: 900px) {
  .page-about .pa-spine {
    margin-left: 56px;
  }
}

.page-about .pa-figure--road {
  margin-top: clamp(32px, 5vw, 56px);
  clip-path: polygon(0 2%, 100% 0, 100% 100%, 0 98%);
}

/* ---------- 团队分工带 ---------- */
.page-about .pa-team-band {
  background: var(--rk-indigo);
  border-top: 1px solid var(--rk-grid);
  border-bottom: 1px solid var(--rk-grid);
  padding: clamp(28px, 5vw, 48px) clamp(20px, 3vw, 36px);
  margin: clamp(28px, 5vw, 52px) 0;
}

.page-about .pa-team-band__head {
  max-width: 40em;
  margin-bottom: clamp(22px, 3vw, 34px);
}

.page-about .pa-team-band__head .rk-kicker {
  font-family: var(--rk-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--rk-mint);
  margin: 0 0 12px;
}

.page-about .pa-team-band__title {
  margin: 0 0 12px;
  font-size: clamp(22px, 2.8vw, 30px);
  font-weight: 500;
  line-height: 1.26;
  letter-spacing: -.01em;
  color: var(--rk-paper);
}

.page-about .pa-team-band__note {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--rk-mist);
}

.page-about .pa-team-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--rk-grid);
  border: 1px solid var(--rk-grid);
}

@media (min-width: 760px) {
  .page-about .pa-team-list {
    grid-template-columns: repeat(4, 1fr);
  }
}

.page-about .pa-team {
  background: var(--rk-indigo);
  padding: 22px 18px 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  outline: none;
  transition: background .18s var(--rk-ease);
}

.page-about .pa-team:hover,
.page-about .pa-team:focus-visible {
  background: #223menschen;
}

.page-about .pa-team__num {
  font-size: clamp(34px, 4.4vw, 48px);
  font-weight: 500;
  line-height: 1;
  color: var(--rk-mint);
  letter-spacing: .02em;
  border-bottom: 1px solid var(--rk-grid);
  padding-bottom: 14px;
}

.page-about .pa-team__role {
  font-size: 15px;
  font-weight: 600;
  color: var(--rk-paper);
  letter-spacing: .02em;
}

.page-about .pa-team__duty {
  font-size: 13px;
  line-height: 1.7;
  color: var(--rk-mist);
  opacity: .55;
  transition: opacity .18s var(--rk-ease), color .18s var(--rk-ease);
}

.page-about .pa-team:hover .pa-team__duty,
.page-about .pa-team:focus-visible .pa-team__duty,
.page-about .pa-team:focus-within .pa-team__duty {
  opacity: 1;
  color: var(--rk-mint-soft);
}

/* ---------- 协作与用户 ---------- */
.page-about .pa-section--panel {
  background: var(--rk-navy-2);
}

.page-about .pa-partner-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--rk-grid);
  border: 1px solid var(--rk-grid);
  margin-bottom: clamp(32px, 5vw, 56px);
}

@media (min-width: 700px) {
  .page-about .pa-partner-row {
    grid-template-columns: repeat(2, 1fr);
  }
}

.page-about .pa-partner {
  background: var(--rk-navy-2);
  padding: 24px 20px;
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-about .pa-partner__num {
  font-size: clamp(32px, 4vw, 44px);
  font-weight: 500;
  line-height: 1;
  color: var(--rk-amber);
  letter-spacing: .02em;
  flex: none;
}

.page-about .pa-partner__label {
  font-size: 14px;
  line-height: 1.65;
  color: var(--rk-mist);
}

.page-about .pa-audience {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3.5vw, 40px);
}

@media (min-width: 760px) {
  .page-about .pa-audience {
    grid-template-columns: repeat(3, 1fr);
  }
}

.page-about .pa-stat {
  display: flex;
  flex-direction: column;
  gap: 12px;
  border-top: 1px solid var(--rk-grid);
  padding-top: 18px;
}

.page-about .pa-stat__num {
  font-size: clamp(40px, 6.4vw, 76px);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--rk-mint);
}

.page-about .pa-stat__unit {
  font-size: .42em;
  margin-left: .12em;
  color: var(--rk-mint-soft);
  letter-spacing: .02em;
}

.page-about .pa-stat__label {
  font-size: 14px;
  line-height: 1.7;
  color: var(--rk-mist);
}

.page-about .pa-audience__note {
  margin: clamp(28px, 4vw, 44px) 0 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--rk-mist);
  border-left: 2px solid var(--rk-amber);
  padding-left: 16px;
  max-width: 40em;
}

/* ---------- 旧资料对照 ---------- */
.page-about .pa-archive {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(32px, 5vw, 64px);
  align-items: start;
}

@media (min-width: 960px) {
  .page-about .pa-archive {
    grid-template-columns: 4fr 7fr;
  }
}

.page-about .pa-archive__aside .rk-kicker {
  font-family: var(--rk-mono);
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--rk-mint);
  margin: 0 0 14px;
}

.page-about .pa-archive__title {
  font-weight: 500;
  font-size: clamp(23px, 3vw, 32px);
  line-height: 1.26;
  margin: 0 0 26px;
  letter-spacing: -.01em;
}

.page-about .pa-archive__steps {
  list-style: none;
  margin: 0 0 22px;
  padding: 0;
  display: grid;
  gap: 18px;
  border-top: 1px solid var(--rk-grid);
  padding-top: 22px;
}

.page-about .pa-step {
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 14px;
  align-items: start;
}

.page-about .pa-step__num {
  font-size: 13px;
  color: var(--rk-amber);
  letter-spacing: .08em;
  padding-top: 3px;
}

.page-about .pa-step__text {
  font-size: 14px;
  line-height: 1.72;
  color: var(--rk-paper);
}

.page-about .pa-archive__hint {
  margin: 0;
  font-size: 13px;
  line-height: 1.72;
  color: var(--rk-mist);
  padding-left: 16px;
  border-left: 1px solid var(--rk-mint);
}

.page-about .pa-archive__body {
  position: relative;
}

.page-about .pa-archive__body::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 0;
  bottom: 0;
  width: 1px;
  background: linear-gradient(180deg, var(--rk-mint), transparent 62%);
  display: none;
}

@media (min-width: 960px) {
  .page-about .pa-archive__body::before {
    display: block;
  }
}

.page-about .pa-archive__links {
  list-style: none;
  margin: clamp(28px, 4vw, 40px) 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--rk-grid);
  border: 1px solid var(--rk-grid);
}

@media (min-width: 700px) {
  .page-about .pa-archive__links {
    grid-template-columns: repeat(2, 1fr);
  }
}

.page-about .pa-archive__links li {
  background: var(--rk-navy);
}

.page-about .pa-archive__links a {
  display: block;
  padding: 16px 18px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--rk-mint-soft);
  text-decoration: none;
  transition: background .18s var(--rk-ease), color .18s var(--rk-ease);
}

.page-about .pa-archive__links a:hover,
.page-about .pa-archive__links a:focus-visible {
  background: var(--rk-indigo);
  color: var(--rk-paper);
}

/* ---------- 焦点可见性 ---------- */
.page-about a:focus-visible,
.page-about summary:focus-visible,
.page-about [tabindex]:focus-visible {
  outline: 2px solid var(--rk-focus);
  outline-offset: 3px;
}
<<<END>>>